Connecting Acer Aspire 3680 to internet wirelessly

I have a new Acer aspire 3680 with Vista and I’m trying to wirelessly
connect it to the internet. I also just bought and set up a Linksys
Wireless G router. The laptop detects and is connected to the wireless
network just fine but the internet doesn’t work (unless I plug in the
ethernet, then it connects that way).

It is connected to the network but just can’t get online. I have another
desktop machine connected by ethernet to the router (which is a Linksys
Wireless G) and it accesses the internet just fine.

I have only the most basic understanding of networks- please help-
thanks! I saw another post on this but the description of what to do
was over my head.